A four-year-old boy suffered a "jackpot" of injuries which suggested he had been abused, a court heard.

Dr Avlon Propst said John Smith was covered in bruises when he was brought into her at the Royal Sussex County Hospital, Brighton.

Staff were shocked when they saw him. One said: "Oh f***", and another said: "Jesus Christ".

She said besides bruises she saw a bite mark on his left forearm and its position suggested the boy could not have caused it himself. The mark was also too big to have been John's.

One bruise behind the boy's left ear would have been difficult for him to have caused, indicative of child abuse.

Dr Propst told Lewes Crown Court yesterday: "This child's injuries are highly suggestive of non-accidental injury and not consistent with self-inflicted injury.

"It was the sheer number of bruises, the sheer quantity . . . this child had hit the jackpot."

Earlier, the court was told how the boy died on Christmas Eve 1999. He had 54 external injuries and four adult bite marks.

John's adoptive parents, Simon and Michelle McWilliam, of Gardner Road, Fishersgate, Southwick, deny cruelty.

Cross examined by Lord Thomas, for McWilliam, Dr Propst said she was told at the hospital that John was a chronic self-abuser, something she had not heard of before in a child of his age.

She said his injuries and the bite mark were not consistent with him throwing himself downstairs, even several times.

Dr Propst said the boy's was one of three cases she remembered best in the past ten years.

Sister Valerie Breen was working at King's College Hospital, London, when John died.

She said Mrs McWilliam cried as she told how John would jump from stairs and bang his head, yet any pain he suffered never seemed to bother him.

McWilliam began to cry as his wife held the boy before he died and said: "He was a lovely boy."

Detective Sergeant Judy Buchan said McWilliam told her he had seen some of John's hair sticking out of wallpaper where the boy had banged his head at their home.

Mrs McWilliam told her he had thrown himself against a radiator and then punched her.

The officer said Mrs McWilliam said she had found the boy unconscious in bed at their home, cuddling his favourite dinosaur toy. His eyes were open and staring.

She slapped his face to stir him but there was no response. She then dialled 999.

The trial continues.